P4A093: Association of Proteinuria on Admission and Clinical Outcomes in Hospitalized Pediatric Patients

Background: Acute kidney injury (AKI) is a common complication in hospitalized pediatric patients. The objective of this study is to evaluate if the presence of proteinuria on admission in a hospitalized child is associated with AKI severity as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) stage criteria, need for renal replacement therapy, critical care service requirements, and mortality at 30 days post-admission.

Methods: This is a retrospective cohort study using TriNetX electronic health record data of patients 2 to 18 years of age who were initially coded for hospital services, underwent urinalysis laboratory testing on hospital admission, had 3 subsequent days of hospital or critical care services billing codes, had three consecutive days of creatinine levels, and no pre-existing renal-related complex chronic condition. The presence or absence of proteinuria was determined from a urinalysis performed on hospital admission, defined as either a text value of “positive” or a numeric value of greater than 15.0 mg/dL, including trace proteinuria. This study evaluated for the frequency of AKI as defined by KDIGO criteria, requirement for renal replacement therapy, mechanical ventilation, or inotropic/vasopressor support, and mortality at 30 days post-admission using the Fisher’s exact test for categorical variables and odds ratios with univariate analysis.

Results: This study included a total of 971 patients [435 (45%) with proteinuria on admission] with a median admission age of 9.7 ± 5.0 years. Proteinuria on admission was associated with an increased odds for AKI (OR 2.41, CI 1.8–3.23, p< 0.001) with a predominance of stage 3 AKI on each day of hospitalization (p < 0.00001), need for renal replacement therapy (OR 5.08, CI 1.69–15.3, p=0.002), and mortality at 30 days post-admission (OR 10, CI 1.25–80.5, p=0.013). Proteinuria on admission was not associated with increased need for critical care services during hospitalization (OR 1.18, CI 0.741–1.89, p=0.55), need for mechanical ventilation (OR 0.559, CI 0.286–1.09, p=0.11), or use of inotropes or vasopressors (OR 0.485, CI 0.526–1.33, p=0.49). Confounding variables of NSAID use and pre-existing complex chronic conditions diagnosed at least two weeks prior to hospitalization were not associated with an increased incidence of proteinuria.

Conclusion: This study suggests that children with proteinuria on admission may have an increased odds of higher severity AKI during hospitalization, need for renal replacement therapy, and mortality at 30 days post-admission. As there were no signs of increased critical care service requirements, illness severity may be underrecognized in hospitalized children with proteinuria. While further prospective study with an increased sample size is needed for in-depth analysis, urinalysis remains a vital tool in detecting AKI and may predict disease severity.